The present invention relates to an incinerator having an airpipe for inducting combustion air into a furnace, especially a furnace having a sectional structure comprising an injection block, a flue block and an intermediate block inserted between the above two blocks according to the required furnace capacity.
It is known that each block of the sectional structure has an airpipe. Each airpipe may uniformly provide combustion air into the furnace. The capacity of the furnace can be increased by adding or changing the intermediate block. Providing uniform air to the furnace produces less harmful gas because of the efficient combustion. The sectional structure may also easily provide for several kinds of incinerators having different burning capacities by changing the pipe connections and the blowing power from the exterior of the furnace.
Each block of the sectional structure also has a steel outer wall coated with an inner refractory lining layer, ensuring long, safe operation. Still, a steel airpipe will be easily worn out by oxidation by being subjected to a constant high temperature. The tip portion close to an end wall suffers more severe losses than other portions of the airpipe. The combustion air's cooling is not sufficient for the tip portion and cracks at the pipe end caused by welding the end wall induce the oxidation. Finally, the end portion of the airpipe drops off the end wall and opens a straight path that prevents the uniform jet of combustion air through the airpipe and forces replacement of the whole airpipe.
The airpipe is also directly coated with the refractory lining of the outer wall. Therefore, the replacement of the airpipe requires very laborious work to break the strong refractory layer.
A blower for the airpipe will suspend operation immediately after an access door begins to open. Stopping the blower acts to suppress the flame from shooting out the refuse access port by stopping the supply of pressurized air into the furnace through the airpipe. Still, there is a small unavoidable time lag before the pressure in the furnace drops to atmospheric level after starting to open the door. Therefore, an operator in front of the access port cannot work safely because of the possibility of the flame shooting through the opening.